Ethiopian Haile Gebrselassie poses for photographers during a news conference in Vienna, Austria. (HERWIG PRAMMER/REUTERS)

Haile Gebrselassie, widely considered the greatest distance runner ever and the only person to run a marathon in less than 2 hours 4 minutes, was heavily favored to win the New York City marathon last November.

But hampered by a knee injury, the two-time Olympic champion at 10,000 meters dropped out and then stunned his followers with the announcement that he was retiring, effective immediately, and ending his bid to win the 2012 Olympic marathon in London. Eight days later, however, he reversed himself and put London back on his agenda.

Sunday the Ethio­pian will run his first race at a major venue since that announcement, when he tackles a half-marathon in Vienna, Austria. Gebrselassie, 37, won a 10K in Angola on New Year’s Eve but pulled out of the Tokyo marathon in February after hurting his knee in a fall.

“It wasn’t healing, and I was uncertain about it,” Gebrselassie said in an interview in Addis Ababa, Ethiopia last month. “At this time, my problem is that if I’m not in very good shape, I don’t want to compete, because it’s not good for me to be saying ‘I dropped out here, I dropped out there.’”

Gebrselassie, who has set 27 official or unofficial world records, has always made prudent career choices, but he is now more cautious than in some of his past attempts to meet great expectations. The man who once famously refused to even discuss retirement also has begun to contemplate that day seriously.

In Ethiopia, Gebrselassie’s fierce determination, as well as his successful pursuit of gold at the 2000 Sydney Olympic 10,000 meters despite an Achilles tendon injury, popularized the Amharic language word “Yichalal,” meaning “It is possible” or “It can be done.”

That injury required surgery and eventually cost Gebrselassie the 2001 world championship at 10,000 meters. Yet he said at the time that he didn’t believe the injury kept some fans from believing he would win.

“Even if I were racing with a cane,” he said jokingly, “there are people in Ethiopia who would say, ‘Haile Gebrselassie can win, Haile Gebrselassie must win.’”

Gebrselassie encountered more of his countrymen’s faith as he rode the bus to the 2010 New York marathon start with an injury. “You can overcome it,” fellow Ethiopian Gebre Gebremariam said he told him. Gebremariam would go on to win the race.

“It’s a race, and you say, well, let me try,” Gebrselassie said in the March interview in Addis Ababa. “What happened in New York was too emotional, but what could I do? The expectations” — his own and those of others — “were so high.”

“That affected me when things happened the way they did and I dropped out,” he added.

At the Nekemte 10K in Ethi­o­pia, where Gebrselassie made a celebrity appearance a week after his retirement announcement, someone held up a sign that said in Amharic, “Yichalal, Haile, until the London Olympics.”

“People told me ‘you have to run,’ ” said Gebrselassie. “They expressed their genuine feelings to me and I was persuaded to continue.” He added, “Among the things that many people commented on and that touched my heart was that they said ‘We’re not saying Haile should never retire, but that his retirement should not take place in this manner.’ ”

That sentiment has been expressed by Ethiopian fans such as accountant Haddis Tafari of Burke, and his wife, Marta Bobass, who have attended Gebrselassie’s races around the United States, including the 2006 Phoenix half-marathon where he set a world record.

“I’d like to see him run more races and do a farewell tour around the world,” said Tafari after Gebrselassie quit the New York marathon while under the Queensboro Bridge’s upper deck. “It’s almost like he went into a tunnel and never came out.”

“I don’t want to see him leaving the stage with bitterness,” said Gebrselassie’s friend Paul Tergat of Kenya, who took silver in the Olympic 10,000 meter race in 1996 and 2000. “He can still win a big marathon.”

Whenever Gebrselassie retires, Tergat said, “he should leave the stage with a lot of passion, the passion he has shown for many years.”

Gebrselassie — who also manages successful businesses in Ethiopia including in Asela, the home town of his youth — has his short-term race schedule set. The Olympic marathon is now just 16 months away. After the Vienna half-marathon, he will run a 10K in Manchester, England, he said.

But somewhere in the distance, he knows he will run his last race one day. “I might stop competing, but running — how could I ever stop?” he asked. “Whether I compete or I don’t compete, I will never quit training.”